Conventional parking sensor systems generally employ ultrasonic proximity sensors, wherein up to twelve or more sensors can typically be arranged around the respective vehicle. In order to avoid disruptive interference and echo-effects, these sensors each emit an ultrasonic pulse sequentially, wherein in each case the other sensors record the echo signals. In this context, each of the sensors can be used with a period of e.g. 200 ms. The distance from an object located in the vicinity (typically up to a maximum distance in the range of from to 2 meters to 4 meters) is then estimated on the basis of signal processing algorithms. If a plurality of echo signals is necessary to identify an object and to estimate a distance thereto, the time resolution and spatial resolution which can be achieved with such ultrasonic-based parking sensors is very limited.
EP 2 623 398 A1 discloses, inter alia, a method for defining a target position of a vehicle in a parking space and a driver assistance system, it being possible to determine two-dimensional and three-dimensional surroundings parameters of the parking space, and the provisional target position of the vehicle in the parking space being corrected on the basis of the three-dimensional surroundings parameters, for example taking into account at least one distance information item.
EP 1 495 344 B1 discloses, inter alia, a parking aid system and a method for operating same, the length and/or width of the parking space being determined from the values of sensors measured while the vehicle travels past a parking space, and the measurement being carried out at different time intervals by means of a distance sensor.
DE 10 2011 086 245 A1 discloses, inter alia, a method for assisting a driver during a parking maneuver, possible trajectories along which the vehicle can be guided into a space during a parking maneuver being determined after the sensing of the surroundings of the vehicle, for example using distance sensors, and the space being output as a parking space to the driver if the vehicle remains within predefined limits during the entire parking maneuver.